Valve woos gamers with free Portal download

Game download Meister Valve has today made the puzzle game Portal available on its Steam network for free.

Yes, both PC and Mac versions cost nothing to download from the site until September 20, 2011.

The give-away is part of promotion that seeks t promote the educational value of games like Portal. "Video games can be used in amazing and unexpected ways to help educate our next generation," according to the Learn with Portals web site.

Apparently: "Innovative educators are finding ways to incorporate Portal and Portal 2 into their classrooms—helping teach physics and critical-thinking skills,"

According to this rationale: "Using interactive tools like the Portal series to draw them in makes physics, math, logic, spatial reasoning, probability, and problem-solving interesting, cool, and fun which gets us one step closer to our goal—engaged, thoughtful kids!'"

Whether that's true or not you can find out by downloading the game here.